This is a magnetic focus and deflection CRT with a flat face. The screen is described as OO9 (Orange/Orange/very long persistence) with an aluminium backing. The prototype is C211Q/X2.
The EVS data for this CRT states the fluorite coating must not contain beryllium. The neck was to be coated with Acheson Dag no. 490 and two coats of Bakelite varnish V130/1.
This CRT came packed in a box whose label indicates it was sent to HMS Collingwood in 1972.